Electric-motor-controlling apparatus.



H. W. LEONARD. ELECTBIIC MOTOR CONTROLLING APPARATUS..

. APPLICATION FILED MAY 11, 1909. 9 4,51 1 Patented Feb. 14, 1911.

2 SHEETSSHEBT 1.

a Vi 11 a a an o v:"ZMAJm Ltbz I I 11.111 I H.. W. LEONARD. ELECTRIC MOTOR CONTROLLING APPARATUS.

APPLICATION FILED MAY 11, 1909.

984,51 1 Patented Feb. 14, 1911 '2 SHEETSSHEET 2.

5 new 'roz mlalw $3; 1 42) Gum/M21 0 HARRY WARD LEONARD, OF BRONXVILLE, NEW YORK.

ELECTRIC-MOTOR-CONTROLLING AQPARATUS.

Specification of Letters latent.

Patented Feb. 14, 1911.

Original application filed January 23. 1905, Serial No.- 242,203. Renewed February 20,1907, Serial No.

' 358,417. Divided and this application filed May 11, 1909. Serial No. 495,357.

To all whom it may concern:

Be it known that I, HARRY WVARD LEONARD, a citizen of the United States, residing at Bronxville, in the count of \Vestchester and State of New York, h ve invented certain new and useful Improvements in Elecing implication filed January 23, 1.905, Se-

rial ho. 2 12,2013; renewed February 20,1907, Serial No. 358,417, granted December 13, 1.910, Patent No. 978,193.

By my invention I provide controlling means for each element of the motor and the controlling means of one element are functionally related to those of the other so that they are necessarily operated in a proper mannen. I therefore protect the mo-' tor and other portions of its circuit from the objectionable or injurious eii ects due to improperly starting up or operating a motor when the strength of its fieldis less than a desirable amount. I also provide suitable protective devices which will respond to pro, tcct the motor under abnormal conditions, all oi which cooperate to secure freedom to the motor from any harmful effects.

My invention may be embodied in various arrangements and forms of construction, some of which are shown in the accomp-an ing drawings, and the form illustrated in each figure comprises my invention and represents one specific embodiment thereof.

Figures 1 to 6 of the drawings are diagrammatic views illustrating preferred forms of my invention, each showings modification different from that shown in the other views.

Similar parts are indicated by. the same reference character in eachiof the figures.

Referring to Fig. '1, the supply terminals of a constant electromotive force circuit are indicated at- 1, 2, the motor. armature at 3, and the motor field'at 4. A starting resistance is shown connected in the armature circuit and a resistance for varying the field strength is indicated at 6. he starting rheostat isin this instance provided with two arms 7, 8 pressed toward each other by a spring 9. The arm 8 serves as a main overload switch and normally engages a fixed contact 10, being retained in position by a catch 11., The latter is adapted to be thrown by the upward movement of core 12 when an abnormal current flows through its coil 13. The coil 13 is connected in the main circuit from 1, to contact The arm 7 is shown in the off position and in this position closes the switch or arm 8 as, for example, by engagement of an abutment. 14. A no-voltage or low voltage magnet 15 is provided for holding the arm 7 when all starting resistance is cut out: The control-' ling arm 16 of the field rheostat is not spring pressed, but there is provided an arm 17 and spring 18, which spring tends to force arm 17 against the arm 16 and throw the latter to such a position that all Y field resistance is out out. A retaining net 19 is provided for the arm 17 and ltS 'coil is connected in series with coil 15 and a resistance 20 across the line. When the current supply is interrupted, or a very low voltage occurs, the magnets 15 and 19 are denergized, 01' their strength reduced, the arm 7 returning to the off position by pressure of spring 9 and the arm 17 is forced against the arm 16, returning'it to such a position that all the field resistance is cut out as shown. Hence, upon starting, the field will alwa s have its full strength, and the objections le effects of starting under a weak field are avoided. In starting, the arm 7 is moved to the first contact of the starting resistance and the circuit through the armature and resistance .5 from the sup-. ply mains is completed The motor field 15 then fully excited, current passing from ,1, through the overload coil 18, arms 8 and 7, condu r 21, field 1, arm 1-6 to terminal 2.. Current also passes independently across the line through coil 15, resistance 20, and coil 19. As arm 7 is moved, the starting resistance is cut out and when the arm reaches its final position, it will be held by the mag not 15-.- The arm 7 may in some cases be i provided with an auxiliary contact 22 which engages the contact 23 at the final position.

This will connect the-field directly across the line. When it is desired to weaken the -vary'the field resistance and therefore the speed of the motor. If an abnormally large current or overload is taken'by the motor, the core-12 will be raised and knock the latch 11 to release arm 8, breaking the main circuit at the contact 10. This will deenergize the magnets 15 and 19, and cause the field rheostat arm 16 to be forced to its initial position, cutting out the field resistance and insuring a full field strength upon starting. Before again starting, it is necessary to move the switch 8 to its closed position by means of arm 7 thus msuring the closing of switch 8 before the circuit is closed by the starting arm 7.

In Fig. 2 a construction is disclosed which is in general similar to that of Fig. 1. The controlling arm 24: of the field rheostat 1S spring pressed, however, as by spring 25. The arm has a toothed sector 26, the teeth of which are engaged by a pivoted lever 27, the action of gravity tending to keep the lever and teeth in contact. The retaining magnet 19, when energized tends to force one end of lever 27 into engagement with the teeth and with a sullicient amount of force to overcome the pressure of the spring 25, thus holding the arm in any position desired. lVhen, however, the magnet is decnergizcd, the spring 25 will return the armto the position shown, the teeth slipping by the end of lever The field resistance is thus cut out and starting under full field strength is insured. After starting, the arm 24: may be operated manually, overcoming the spring pressure and. the force of holding lever 27.

In Fig. 3 a construction is indicated inwhich the starting rheostat and overload and lie-voltage devices are similar to those shown in Fig. l The controlling arm 4-1 of the field rheostat is, however, provided with a toothed rack engaged by a worm 45 on the shaft of a small motor 46. This motor is connected by wires ii to the outside contacts of the armature resistance 5, or if desired to intermediate contacts thereon. The mi" ':-r 16 is therefore subjected to the drop in ts which occurs on the starting resistance and when driven, turns in a direction so to cut out any field resistance which happen tobe in. circuit. When the arm 7 is moved to the first contact in starting, the motor i6 is subjected to the drop occurring between the terminals of wires 47 and the motor at will be driven so as to move the field rheostat arm to the posit-ion shown,

giving the field its full strength. The resistance 5 will thereafter be cut out only under-condition of a full field. I'Vhen all of the armature resistance is cut out, the motor 26 an have no further tendency to turn.

Fig. 1. An arm 16 is freelymovable over the field resistance 6 and is adapted to engage an abutment. 74- on arm 75 to force the same against 'the' pressure of spring :76 to engage the no-voltage or low voltage magnet- 19. The latter is connected in series with the novoltage magnet 15 and resistance 20 across the line as in Fig. 1. Upon the occurrence of a low voltage, the spring '76 will throw the arm 75 against a stop 77] In this position the arm 75 engages a contact '78 in electrical connection with the initial contact of the field resistance, and forms a directpath for the field current from the field coil through arm 75 to terminal 2. Any field resistance cut in by arm 16 will therefore be short-cireuited by arm 75 and starting under a full field is therefore insured. After starting. the arm 16 may be moved to remove the short-circuiting arm 75 and force the same against the magnet 19, where it will be held, and arm 16 may then be moved to vary the resistance in the field circuit.

In Fig. 5 the magnet- 19 will hold one end of the pixoted lever 79 against the pressure of spring 80 under running conditions. When released by the magnet, the lever will engage a contact 81 which is in electrical connection with the initial contact of the field resistance. The lever is in electrical connection with the terminal 2. The cugagement of the lever with contact 81 will therefore short-circuit the field resistance, there being a direct connection from the field coil to contact 31, through lever '79 to terminal 2. Starting will. therefore necessarily occur under full field strength. After starting, the arm 82 must he moved to the initial contact and by mcans of the extcnsion 83, throw the lever 79 out of engagement with contact 81 and intmposition to be retained by magnet 19. This will remove the short-circuit of the resistance 6 and the field strength may then be changed as desired.

n Fig. 6 I show a form of starting rheoscribed. The field resistance is indicated at 84 and the amount of this resistance in cirand overload device previously de-.

dropped in them.

sistance and field coil. Arm 7 is provided with an abutment or projection 89, and when the arm 7 returns under ressure 9 to oft position it will engage t e lever 87 and force it to engage contact 88. Hence, upon starting, any field resistance in the circuit will be short-circuited by the ath through love-r87 and contact 88 to the old coil, giving the field its full strength. In order to remove the short-circuit after starting, it will. be necessary to move the element 85 to cut out all field resistance and to engage lever 87 so as to causeit to break connection With contact 88. The element 85 may then be moved to cut in the field resistance and vary the field strength as desired.

Many other modifications of my invention may be developed and various changes in the connections may be made and accomplish substantially the same results. I

It will be understood that instead of using a starting rheostat contact switch, I may, in some cases. omit the starting resistance and use a plain switch. I may sometimes use a controlling armature resistance for varying the speed, in which case the arm of therheostat would be freely movable and rema-inin any position placed.

Although. I have indicated resistances in the circuits of some of the coils which act automatically to cause a. circuit to be opened, it will be understood that in some cases they may not be necessary and may be made adjustablc if desired to change the volts As my invention is susceptible of avariety of embodiments, all Within the scope and spirit thereof 1 do not wish or intend to limit the same to the specific constructions herein described, or otherwise than as expressed 1]] the following claims.

Having thus described my invention, I declaro that what. I claim as new and desire to sccure'by Letters Patent, is

1. Means for controlling an electric motor circuit comprising armature control mechamsm, n'icans for retaining the same in short by the armature control mechanisi'n for rendering) the said return means inoperative.

Means for controlling an electric motor circuit com )rising armature control mechanism biased to the starting position, field control mechanism, means normally tendin to return said latter mechanism to full field position and means controlled by the armature controlling mechanism for rendering the said returning means inoperative.

3. Means for controlling an electric motor circuit comprising arn'iature control mechanism, field control mechanism, means normally tending; to return said latter mechanism t full fi ld position and a no-voltage magnet controlled by the armature controlled mcchanism for controlling the returning means.

4-. Means for controlling an electric motor circuit comprising armature control mechanism biased to the starting position, field control mechanism, means normally tending to return said latter mechanism to full field position and a no'voltage magnet controlled by the movement of the armature control mechanism from running position for ren dcring the said returning mechanism inopcrative.

5. Means for controlling an electric motor circuit comprising armature control mechanism biased to the starting position, a no voltage magnet therefor, field control mechanism, means normally tending to return said latter mechanism to full field )OSltlOll, and a no-voltage magnet controlled by the movement of the armature control mechanism from running position for rendering the said returning mechanism inoperative.

6. Means for controlling an electric motor circuit. comprising armature control mechanism, field control mechanism, means normally tending to return said latter mechanism to -full field position and electrically controlled means responsive to movement of the armature control mechanism from running position for rendering the said returning means inoperative.

7 Means for controlling an electric motor circuit comprising armature control mechanism, field control mechanism, means normally tending to return said latter mechanism to full field position and means responsive to movement of the armature control mechanism for controlling the returning means.

8. In combination with. a dynamo electric machine, armature controlling means, and field controlling means, said field controlling means comprising means for manually and aut'on'iatica-lly controlling the field circuit and said field controlling means comprising two mechanically related independently movabloelements, one of which is an element of the field rheostat, and said field controlling means being electrically controlled by said armature controlling means.

9. In combination with an electric motor, armature controlling means therefor, and field controlling means therefor, said field controlling means comprising two mechanically related independently movable elements, and said field controlling means being electrically controlled by said armature controlling means. I

10. The combination with an electric motor, of an armature resistance device therefor having a movable element, field controlling means electrically controlled by said movable element, said field controlling" means comprising a normally restrained automatically movable eleniaent responsive to low volt-age.

11. The combination with an electric motor, of controlling means therefor adapted to independently vary the armature and field energies of the motor, said means comprising three functionally related automatically movable contact making elements, two of said three elements being mechanically related and one of said three elements being a field controlling element, and means comprising a low voltage winding controlling said latter element, the circuit of said low voltage winding being controlled by each of the other two elements.

12. An electric motor, and motor control- .i'g means therefor adapted to independvary the energy in the armature and d windings of the motor, said means comng three automatically movable elements, two of which are, mechanically related and independently movable and adapt- .ed to control, the circuit of the field winding of the motor and the third of which is adapted to control the motor armature circuit and also to control the automatic movement of the said two mechanically related elements. r

'13. The combination of an electric motor,

and field controlling means therefor comprising two mechanically related movable elements, one adapted to be normally restrained and to be automatically moved upon occurrence of low voltage a low voltage electro-responsive device therefor, means whereby said element is automatically moved when released, the other of said movable elements being the movable element of a field rheostatio device, and functionally related automatically movable means adapted to contro 'said field controlling means.

15. An electric motor, an armature controlling automatically movable element, restraining means therefor responsive to low voltage, afield-controlling automatically movable element,- restraining means therefor responsive to low voltage, the circuit of the last mentioned restraining means being controlled by the said armature controlling movable element.

16. An electric motor, and means for controlling said motor, comprising two low voltage electro-responslve devices, the windings of which are connected in series with each other, one of said devices controlling the field c1rcu1t of the motor.

17 An electric motor, and means for controlling said motor, comprising two func tionally related low voltage windings, one of which is adapted to control the field current of an electric motor and is controlled through the agency of the other of said windings.

i In testimony whereof I aiiix my signature, in presence of two witnesses.

H. WARD LEONARD.

W'itnesses:

C. J. CORNELL,

Gno. J. SormLz, Jr. 

